Will the U.S. Chase the Islamic State as It Moves Into Central and Southeast Asia?

Today the grueling battles to expel the self-styled Islamic State from Iraq and Syria drag on, but even when they are over it will not be the end of the violent extremist movement. There are still willing recruits for the Islamic State and plenty of anger, disillusionment and alienation that it can exploit. Unfortunately, it has established its global “brand.” Even as it is being driven from its homeland, it seems to be plotting its next strategic moves.

At this point, the Islamic State’s most effective foray outside Iraq and Syria is in Afghanistan, where it has joined the Taliban’s long conflict with the elected government in Kabul. Afghan officials estimate that the Islamic State has around 2,000 fighters in the eastern part of the country, many of them foreigners. A few weeks ago, there was a major attack in northern Afghanistan by a force claiming to include both Taliban and Islamic State militants. And the group has claimed credit for suicide attacks in Kabul and Herat. ...